The metadata below describe the original scanning. Follow the "All Files: HTTP" link in the "View the book" box to the left to find XML files that contain more metadata about the original images and the derived formats (OCR results, PDF etc.). See also the What is the directory structure for the texts? FAQ for information about file content and naming conventions.
Bibliography: p. 74
Röntgen, W. C. A new kind of rays.--Further observations on the properties of the X-rays.--Stokes, Sir G. G. On the nature of the Röntgen rays.--Thomson, J. J. A theory of the connection between cathode and Röntgen rays